The proper order of prayer is to begin by praising God and only then to petition Him. We learn this from Moshe, who opened his prayer with words of praise, saying (Devarim 3:24), “Lord, God, You have begun to show Your servant Your greatness and Your mighty hand. What force is there in heaven or earth that can perform deeds and mighty acts as You do?” Only afterwards did Moshe plead, “Please let me cross [the Jordan] so that I may see the good land…” Based on this, Rav Simlai interprets, “One should always praise God first and afterwards pray” (Berakhot 32a). The primary application of putting praise before request is found in the berakhot of the Amida, for as previously mentioned (12:9), the first three berakhot open with words of praise and only later continue to the petitionary berakhot. However, even in the rest of one’s prayer, it is proper to open with words of praise, and that is the purpose of Pesukei De-zimra.
By reciting Pesukei De-zimra, the person praying reflects upon God’s greatness, and thus when he subsequently stands in prayer, he knows before Whom he stands. Were he not to pray this way, there would be concern that he might come to request his needs like idol worshipers, whose whole aim is their personal success in their lowly matters and who are not interested at all in devoting themselves to God, the Source of life. However, one who purifies his heart through meditation on God’s greatness knows how to pray; even his requests for health and sustenance are so that he may devote himself to God and to rectify the world under the Almighty’s sovereignty. His prayers are thus more genuine and worthy of being accepted (see Olat Rei’yah vol. 1, p.14).
The name “Pesukei De-zimra” (“Verses of Song”) alludes to exactly that, as the word “zemer” can mean song or poem and also pruning or cutting. Just like one who prunes his vineyard cuts off the extra branches in order to strengthen the growth of the branches that will produce good fruit in the future, by saying Pesukei De-zimra the person praying destroys his flawed thoughts and bad feelings, and diminishes the laziness that accumulated as a result of sleep, so that he can pray with kavana. This cleansing in advance of prayer is pleasing and enjoyable for within it there is song and praise; therefore, it is called “Pesukei De-zimra” (see Peninei Halakha: Prayer, ch. 14 n. 2).